Bats and dolphins emit sound waves to sense their surroundings; like a battery, electric fish generate electricity to help them detect motion while burrowed in their refuges; and humans use tiny movements of the eyes to perceive objects in their...

In the 1990s, Jack Kevorkian controversially brought the issue of physician-assisted dying to the forefront of a conversation at the crossroads of medicine, technology, law and morality — known as bioethics.